Improvement in bit-stocks



Patented Nov. 24, 1874.

Bit-St ll- L E H c T M s .L

EB. Z Q

UNITED STATES PATENT QFFICE.

JOHN S. MITCHELL, OF NEWARK, NEW JERSEY.

IMPROVEMENT IN BIT-STOCKS.

Specification forming part of Letters Patent No. 157,212, dated November 24, 1874; application filed June 25,1874.

To all whom it may concern:

Be it known that I, JOHN S. MITCHELL, of the city of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Bit- Stocks; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention consists in combining a spiritlevel with an ordinary carpenters brace or bitstock, the object of which is to secureaccuracy in leveling a bit or drill, or obtaining the perpendicular or any desired angle of the same, while boring or drilling.

Figure l is a side elevation of my invention. Fig. 2 is a sectional view of the same.

The spirit-level A is attached just in the rear of the socket. The brace being recessed at the point for the purpose, the level is provided with a round shank, which passes through the brace and is secured by a screwnut, a, on the end of said shank.

The level is designed to be adjusted to any angle, and the degrees may be indicated on the brace or level for the purpose.

In the present illustration, however, a de- -vice is employed to set the level at right angles, there being a tooth, b, on the shoulder of the level, which fits into corresponding recesses in the shoulder formed on the brace at the proper points to secure a level and perpendicular; but this device is not essentially necessary. The shoulders may be smooth, and, as already observed, the degrees may be simply marked thereon, in which case the adjustment must be sufficiently close and tight as not to be disturbed by the motion of the brace while in use. When the tooth-and recesses above described are used a coil or other suitable spring, (2, is employed in combination with the level, as shown.

The manner of securing the bit in the stock is as follows: A hole passes through the brace intersecting with an angle of the socket, through which a pin, 6, is inserted, said pin having a V-shaped groove cut in its side corresponding with the angle of the socket, as shown, the shank of the bit or drill having a semicircular groove cut across one of its edges corresponding with the size and position of said pin. The pin is turned so that the grooved side is in juxtaposition with the socket. The bit is then inserted in the socket with its grooved side opposite to the pin, which, on being turned partially around brings the conveX side of said pin into the groove formed into the shank of the bit and secures it in position.

I am aware of the patent granted to A. Amory July 27, 1869, No. 92,927, and hereby disclaim the same.

What I claim as HGWyELHd. desire to secure by Letters Patent of the United States, is-

The combination of the bit-stock with the reversible level A, having the nut a, spring 0, and catch 1), substantially as shown and described.

In testimony that I claim the foregoing as my own invention I aflix hereunto my signature in presence of two witnesses.

JOHN S. MITCHELL.

Witnesses Gno. H. WILsoN, Gno. W. FRANCIS. 

